Understanding Taf13 (TATA box-binding protein-associated factor 13) upregulation in eukaryotic cells

Abstract

TATA-binding protein (TBP) and TBP-associated factors (Tafs) comprise RNA Polymerase II (RNA Pol II) pre-initiation complex. This universal component carefully controls the transcriptional initiation process. One of the Tafs, Taf13, also plays an important role in the regulation of RNA Pol II transcription initiation which is evolutionarily conserved from yeast to humans. It is found that Taf13 is overexpressed in cancer cells, although the exact mechanism that is responsible for this overexpression is unclear. Our hypothesis suggests that targeted degradation by the 26S proteasome via ubiquitylation [Ubiquitin-Proteasome System (UPS)] may be the mechanism that regulates the stability of Taf13. To test this possibility, we evaluated the role of UPS on the stability of Taf13 in yeast (Saccharomyces cerevisiae). Importantly for the first time, we found that Taf13 undergoes polyubiquitylation but it is not regulated by the 26S proteasome. These findings suggest further oncologic research topics for the development of therapeutic interventions for future patients of cancer